TESTICULAR CANCER STAGING
Category: Urology
Abstract : Testicular cancer: serum markers Germ cell tumours may express and secrete
into the bloodstream relatively specific and readily measurable proteins. These
tumour markers (with the exception of PLAP) are useful in diagnosis, staging,
prognostication, and monitoring of response to treatment. Onco-fetal
proteins Alpha-fetoprotein (AFP) is expressed by trophoblastic elements
wit
Testicular cancer: serum markers
Germ cell tumours may express and secrete
into the bloodstream relatively specific and readily measurable proteins. These
tumour markers (with the exception of PLAP) are useful in diagnosis, staging,
prognostication, and monitoring of response to treatment.
Onco-fetal
proteins
Alpha-fetoprotein (AFP) is expressed by trophoblastic elements
within 50 - 70% of teratomas and yolk sac tumours.
With respect to seminoma, the
presence of elevated serum AFP strongly suggests a non-seminomatous element.
Serum half-life is 3 - 5 days; normal <10ng/ml.
Human chorionic
gonadotrophin (hCG) is expressed syncytiotrophoblastic elements of
choriocarcinomas (100%), teratomas (40%), and seminomas (10%). Serum half-life
is 24 - 36h. Assays measure the ?-subunit; normal <5mIU/ml.
When used
together, 90% of patients with advanced disease have elevation of one or both
markers; less among patients with low-stage tumours.
Cellular
enzymes
Lactate dehydrogenase (LDH) is a ubiquitous enzyme, elevated in serum
for various causes, therefore less specific. It is elevated in 10 - 20% of
seminomas, correlating with tumour burden, and is most useful in monitoring
treatment response in advanced seminoma.
Placental alkaline phosphatase
(PLAP) is a fetal isoenzyme, elevated in up to 40% of patients with advanced
germ cell tumours. It is not widely used as it is non-specific. May be elevated
in smokers.
Clinical use
These markers are measured at presentation, 1
- 2 weeks after radical orchidectomy, and during follow-up to assess response to
treatment and residual disease.
Normal markers prior to orchidectomy do not
exclude metastatic disease; normalization of markers post orchidectomy cannot be
equated with absence of disease; and persistent elevations of markers post-
orchidectomy may occur with liver dysfunction and hypogonadotrophism, but
usually indicate metastatic disease.
Staging
- Sx Markers not
available
- S0 Markers normal
- S1 LDH 1 - 1.5 Ã normal upper
limit; hCG <5000 mIU/ml; and AFP <1000ng/ml
- S2 LDH 1.5 - 10 Ã
normal; hCG 5000 - 50,000; and AFP 1000 - 10,000
- S3 LDH >10 Ã
normal; hCG >50,000; and AFP >10,000
Testicular cancer: pathology
and staging
90% of testicular tumours are malignant germ cell tumours (GCT),
split into seminomatous and non-seminomatous (NS) GCTs for clinical purposes.
Seminoma, the most common germ cell tumour, appears pale and homogeneous. NSGCTs
are heterogeneous and sometimes contain bizarre tissues such as cartilage or
hair. Metastases to the testis are rare, notably from the prostate (35%), lung
(19%), colon (9%), and kidney (7%).
The right testis is affected slightly
more commonly than the left; synchronous bilateral TC occurs in 2% of cases. TC
spreads by local extension into the epididymis, spermatic cord, and, rarely, the
scrotal wall. Lymphatic spread occurs via the testicular vessels, initially to
the para-aortic nodes. Involvement of the epididymis, spermatic cord, or scrotum
may lead to pelvic and inguinal node metastasis. Blood-borne metastasis to the
lungs, liver, and bones is more likely once the disease has breached the tunica
albuginea.
TC is staged using various classifications, most recently the
TNM (2002) system . Herein, T stage is pathological, N stage involves imaging,
and M stage involves physical examination, imaging, and biochemical
investigations. An additional S category is appended for serum tumour markers.
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